What makes a film funny? Really funny? When it came to compiling a list of the greatest comedy films of all time, tension mounted among Time Out film writers. ‘Well everyone knows “Airplane!” is the funniest film ever,’ said one, as if some divine council of Bob Hope gag writers had ordained it back in the 1980s. ‘It’s good, but it’s no “South Park: Bigger, Longer and Uncut”,’ retorted another (a man who likes his humour as blue as Yves Klein’s front room). I chipped in: ‘But what about Jacques Tati’s “Playtime” – surely comedy cinema should be measured as much on intellectual weight and visual innovation as the number of fart gags and slide-whistles?’

I didn’t get much response. And so, to prevent a three-way flick-knife battle, we called on a panel of experts to ask what makes great comedy cinema. And who better to tell us what’s funny than those who make people laugh for a living? With the help of the Time Out Comedy and TV sections, we plumbed the depths of our contact books for every comic stand-up, writer, actor or director that we knew and asked them to name their top ten comedy films of all time. Many rose to the challenge. More than 200 to be exact, all diligently listing their personal favourites and, more often than not, offering wry annotations to explain their choices. Stephen Merchant, Edgar Wright, Jo Brand, Russell Howard, Tim Vine and Richard Curtis are just some of those who answered our call. And I can say you haven’t lived until you’ve received an email from Dan Aykroyd listing (in curt, 12pt Courier typeface) his favourite comedy films. Oddly, they include ‘Goodfellas’.

Which brings us back to that old conundrum of what makes great comedy. Probably more than any other genre, comedy eludes easy definition. Funny is subjective. Some people prefer a low chuckle, while others want to be transported to the point where blood vessels start bursting and intestinal tracts erupt in violent spasm.

The 100 films we arrived at – whittled down with an age-old points system – came from a sample of 478, ranging from oddities such as Whit Stillman’s urbane, political romcom, ‘Barcelona’ (1994), through to questionable Ivy League blackface romp, ‘Soul Man’ (1986). But long before we crunched the numbers, it was clear what was going to make it to number one. Rob Reiner’s ‘This Is Spinal Tap’ romped to victory by a staggering margin, appearing on 92 personal top tens.